SERKing Coreceptors for Receptors

SERK family receptor-like kinases are key and convergent modules in diverse signaling pathways governing plant growth, cell differentiation, and immunity. SERKs exist as coreceptors of multiple cell surface-resident receptors perceiving diverse stimuli via ligand-induced heterodimerization and transphosphorylation. Individual SERK members exert distinct functions in different physiological responses with a high degree of functional plasticity and specificity. Layered mechanisms regulate the activation and attenuation of SERK-associated receptorsomes. Convergent and divergent signaling modules function downstream of SERK-associated receptorsomes. Conserved functions of SERKs are being uncovered in crops. Plants have evolved a large number of cell surface-resident receptor-like kinases (RLKs) and receptor-like proteins (RLPs), many of which are implicated in sensing extrinsic and intrinsic signals, and govern diverse cellular responses. The signaling pathways mediated by RLKs and RLPs converge at a small group of RLKs, somatic embryogenesis receptor kinases (SERKs), via ligand-induced heterodimerization and transphosphorylation. As shared coreceptors in diverse signaling receptorsomes, SERKs exhibit functional plasticity yet maintain a high degree of signaling specificity. Here, we review recent advances in newly identified SERK functions in plant cell differentiation, growth, and immunity; discuss the regulation and activation mechanisms of SERK-associated receptorsomes; and provide insights into how SERKs maintain signaling specificity as convergent hubs in various signaling pathways. Plants have evolved a large number of cell surface-resident receptor-like kinases (RLKs) and receptor-like proteins (RLPs), many of which are implicated in sensing extrinsic and intrinsic signals, and govern diverse cellular responses. The signaling pathways mediated by RLKs and RLPs converge at a small group of RLKs, somatic embryogenesis receptor kinases (SERKs), via ligand-induced heterodimerization and transphosphorylation. As shared coreceptors in diverse signaling receptorsomes, SERKs exhibit functional plasticity yet maintain a high degree of signaling specificity. Here, we review recent advances in newly identified SERK functions in plant cell differentiation, growth, and immunity; discuss the regulation and activation mechanisms of SERK-associated receptorsomes; and provide insights into how SERKs maintain signaling specificity as convergent hubs in various signaling pathways. cellular components, such as endogenous peptides, which are released during pathogen attack, cell damage, or death, and trigger or amplify defense responses. proteins secreted by pathogenic microbes into hosts to suppress host immunity or interfere with host physiology. a protein quality check process in the ER that allows the export of only correctly folded secretory and membrane proteins to their physiological destinations. a physiological process whereby the outer floral organs, including sepals, petals, and stamens, are shed from the plant body after fertilization. conserved molecules derived from microbes that may trigger defense responses in hosts. receptor proteins, such as RLKs and RLPs, that may recognize MAMPs or DAMPs. a class of proteins with a cytoplasmic kinase domain resembling that in RLKs yet without the transmembrane and extracellular domains. a class of transmembrane proteins with a diverse extracellular domain, a single transmembrane domain, and an intracellular kinase domain. a class of transmembrane proteins with a diverse extracellular domain, a single transmembrane domain, and a short intracellular region without a typical kinase domain. a cell surface-resident protein receptor complex comprising different RLKs and RLPs that perceive the cognate ligand. a process whereby somatic cells transit to embryogenic competent cells. a process involving in a series of cell divisions and differentiations that form two highly specialized guard cells with a stomatal pore in between.